Creepy! True Tales: Death of Luther McCarty and The Ten Seconds of light

On May 24, 1913, up-and-coming boxer Luther McCarty kissed his wife and young daughter goodbye and headed from his home in Wild Horse Canyon, Nebraska to a boxing ring in Calgary, Alberta where the heavyweight hopeful would face his next opponent, Arthur Pelkey. The match would not proceed beyond the first round and the boxing world would forever wonder how good Luther McCarty could have been. It is said to have been taking place during the referee’s count when McCarty hit the ground. An ethereal shaft of light began as the count began and ended when ten was reached. This light solely illuminated the still body of the fallen boxer and shocked many of those present.
The only known photo taken of this light has been debated ever since McCartys death. Almost immediately, stories began doing the rounds that this photo was somehow faked or is a pure hoax. However, no-one has yet managed to explain how it was done. Many of the audience in Tommy Burns Arena during the brief two minute boxing match say that the light was a genuine occurrence and not faked in any way. This photo is not the only unexplained event to occur in the barn. Legend states that the venue for the ill-fated fight was burned to the ground the following day.

What was this light and where could it have come from? How did it illuminate one fallen boxer while being counted out of the match?